Contamination clean-upNew methods might drastically reduce the costs of investigating polluted sites

New methods may allow polluted sites to be investigated and monitored long term at significantly reduced costs. Authorities and those who have to remediate polluted sites in Europe may therefore be able to save on costs and use the savings to treat other areas. This is the conclusion of the EU research project ModelPROBE ((Model driven Soil Probing, Site Assessment and Evaluation), which was coordinated by the Helmholtz Center for Environmental Research (UFZ) and the results of which were presented on 21 September 2012 at the international REMTECH Expo exhibition in Ferrara, Italy. The results, with which the scientists aimed to lower the workload of authorities and consultants, include a handbook detailing the methods for characterizing contaminated sites and a freely-accessible e-learning course.

A UFZ release reports that in Europe there are over 20,000 complex and large contaminated areas. These so-called megasites threaten scarce land and water resources, create environmental and health risks, and result in economic and social costs. Their efficient and sustainable revitalization requires innovative site assessment and decontamination technologies and integrated evaluation approaches in order to optimize the options for their re-use. A total of fifteen partners from eight countries have therefore developed, within the scope of the EU ModelPROBE project, new methods for the assessment of polluted sites and the associated monitoring of rehabilitation measures. These methods, which are non- to low-invasive in terms of sampling and treatment of the subsoil, were tested, reviewed, and compared with traditional methods at UFZ reference sites such as in Zeitz. The EU has funded this interdisciplinary monitoring to the tune of €3 million.

In order to detect pollution in the subsoil, until now for the most part samples of soil and groundwater have been taken. Pollution may only be detected, however, if the samples are taken at the optimum points and in a sufficiently dense measurement network. Their accuracy determines how well the pollution can be detected. The scientists have therefore worked on time-delayed geophysical measurements in order to improve the accuracy of the probing and also to record the effects of hydraulic changes and microbial activity.

The ModelPROBE project also integrates new methods with which important information on pollution in the soil can be gained for example by analyzing the vegetation. Based on these non-invasive site-investigation methods, the extent of the contamination and the heterogeneity of the subsoil are then localized. “Using direct push probes with linked geophysical and hydrological probing systems and combined with chemical, toxicological and isotope analyses, so-called hot spots are then monitored in order to determine the limits of and identify the contaminated area without fear of legal action,” explains the project coordinator Prof. Matthias Kästner of the Helmholtz Center for Environmental Research (UFZ). Biological processes such as pollutant decomposition and toxic effects at the site are monitored using passive samplers, biosensors and microcosms with subsequent isotope and biomarker analyses. Due to this complex monitoring process, scientists not only from the Environmental Biotechnology Department, but also from the Groundwater Remediation, Monitoring & Exploration Technologies, Bioanalytical Ecotoxicology and Isotope Biogeochemistry Departments were involved.

These methods were tested not only in Zeitz, but also by project partners in Italy, Norway, and the Czech Republic. The aim was to gain a fresh insight into soil and subsoil contamination at different levels including integrated statistical analysis and modeling and to provide a solid foundation for future risk assessments and sustainable rehabilitation concepts.